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Converters · 2026

Data Storage Converter

Convert between bits, bytes, kilobytes, megabytes, gigabytes, terabytes, petabytes and binary equivalents (KiB, MiB, GiB). Essential for developers and IT professionals.

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Data Storage Converter
Bits · Bytes · KB · MB · GB · TB · PB

Enter a value and select units to convert.

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Data Storage Reference

1 GB = 1,000 MB = 1,000,000,000 bytes in the decimal units drive makers and internet providers use, while 1 GiB = 1,024 MiB = 1,073,741,824 bytes in the binary units Windows counts in. That 7.4% gap is why a 1 TB drive shows about 931 GB. The converter handles both systems, plus bits for network speeds.

Two systems exist: the SI (decimal) system used by hard drive manufacturers and the binary (IEC) system used by operating systems. This difference explains why a "1 TB" hard drive shows as 931 GB in Windows.

UnitSI (decimal)Binary (IEC)
Kilobyte1,000 bytes1,024 bytes (KiB)
Megabyte1,000,000 bytes1,048,576 bytes (MiB)
Gigabyte1,000,000,000 bytes1,073,741,824 bytes (GiB)
Terabyte1,000,000,000,000 bytes1,099,511,627,776 bytes (TiB)

This converter uses the SI decimal system (powers of 1,000). For binary units (KiB/MiB/GiB/TiB), exact powers of 1,024 are used.

Why a New Drive Looks Smaller

The drive holds exactly the advertised number of bytes. Windows divides by powers of 1,024 but still labels the result "GB" or "TB", so the number looks lower. macOS (since version 10.6) and iOS count in decimal and show the advertised figure.

AdvertisedBytesWindows showsmacOS shows
128 GB128,000,000,000119.2 GB128 GB
256 GB256,000,000,000238.4 GB256 GB
512 GB512,000,000,000476.8 GB512 GB
1 TB1,000,000,000,000931.3 GB1 TB
2 TB2,000,000,000,0001.82 TB2 TB
4 TB4,000,000,000,0003.64 TB4 TB
8 TB8,000,000,000,0007.28 TB8 TB

Formatting, recovery partitions and the operating system take further space, so the free space on a new computer is lower again. That part is not a unit issue.

Decimal vs Binary: How Far Apart They Drift

The gap grows with every step up, because each binary prefix multiplies by 1,024 instead of 1,000.

Decimal (SI)BytesBinary (IEC)BytesBinary is larger by
kilobyte (kB)103kibibyte (KiB)210 = 1,0242.4%
megabyte (MB)106mebibyte (MiB)220 = 1,048,5764.9%
gigabyte (GB)109gibibyte (GiB)2307.4%
terabyte (TB)1012tebibyte (TiB)24010.0%
petabyte (PB)1015pebibyte (PiB)25012.6%
exabyte (EB)1018exbibyte (EiB)26015.3%

Strictly, the SI symbol for kilo is a lowercase k (kB), and SI prefixes always mean powers of 10. The binary names (kibi, mebi, gibi) exist so that 1,024 based sizes never have to borrow them.

Bits, Bytes and Download Times

Internet plans are sold in megabits per second (Mbps); file sizes are in bytes. Divide Mbps by 8 to get megabytes per second. Times below are the best case at the full plan speed, with no protocol overhead or Wi-Fi losses.

Plan speedMB per second1 GB file50 GB game
25 Mbps3.135 min 20 s4 h 27 min
100 Mbps12.580 s1 h 7 min
300 Mbps37.527 s22 min
500 Mbps62.516 s13 min
1,000 Mbps (1 Gbps)1258 s6 min 40 s

Common mistakes

  • Mb vs MB. A lowercase b means bits, an uppercase B means bytes. 100 Mb is 12.5 MB.
  • RAM is always binary. A "16 GB" memory module holds 16 GiB, which is 17,179,869,184 bytes.
  • Mixing systems in one calculation. Converting TB to "GB" with 1,024 gives a GiB figure. Pick one system and stay with it.
Method and sources. SI prefixes (kilo = 103 up to quetta = 1030) from NIST Special Publication 811 and the SI Brochure, including the ronna and quetta prefixes adopted by the General Conference on Weights and Measures in November 2022. Binary prefixes (kibi, mebi, gibi and so on) from IEC 80000-13, as described by NIST. 1 byte = 8 bits. Drive and download figures in the tables were computed from these definitions.
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Conversion Questions

In the SI (decimal) system: 1 GB = 1,000 MB = 1,000,000 KB = 1,000,000,000 bytes. In the binary system used by operating systems: 1 GiB = 1,024 MiB = 1,048,576 KiB. This is why a drive marketed as 1 TB only shows about 931 GB in Windows: the OS uses binary units.

Hard drive manufacturers use the SI (decimal) definition: 1 TB = 1,000,000,000,000 bytes. Operating systems (Windows, macOS, Linux) historically displayed storage in binary units (GiB, not GB), but labeled them as "GB." So 1 TB drive ÷ 1.0995 × 1012 bytes/TiB ≈ 0.909 TiB, displayed as "931 GB" in Windows. Modern macOS (10.6+) switched to the SI definition, so it shows "1 TB."

In the SI system: 1 KB = 1,000 bytes. In the binary system: 1 KiB (kibibyte) = 1,024 bytes. Historically, "kilobyte" was used for both, causing confusion. The IEC introduced the kibibyte (KiB) in 1998 to be unambiguous. Network speeds are almost always in SI units (Mbps = 106 bits/s). This converter uses SI for KB/MB/GB/TB/PB and binary for KiB/MiB/GiB/TiB/PiB.

A bit is the smallest unit of data, representing 0 or 1. A byte is 8 bits. Network speeds are measured in bits per second (bps, Kbps, Mbps, Gbps). Storage is measured in bytes. So a 100 Mbps internet connection can theoretically download at 12.5 MB/s (100 ÷ 8). Always check whether a speed is in bits or bytes.

In the SI system: 1 TB = 1,000 GB. In the binary system: 1 TiB = 1,024 GiB. When buying storage, manufacturers use SI (1 TB = 1,000 GB). When your OS reports storage, it may use binary. A 1 TB SSD shows as 931 GB in Windows (binary) or 1 TB in modern macOS (SI). Both statements are technically correct under different definitions.

Divide Mbps by 8 to get MB/s. Example: 100 Mbps ÷ 8 = 12.5 MB/s. Internet speeds are marketed in megabits per second (Mbps). Download managers show progress in megabytes per second (MB/s). So a "gigabit" (1,000 Mbps) connection gives approximately 125 MB/s maximum download speed.

In the SI system: 1 PB = 1,000 TB = 1,000,000 GB = 1015 bytes. Major cloud providers store exabytes of data (1 EB = 1,000 PB). An hour of 4K video is roughly 25 GB, so 1 PB holds approximately 40,000 hours of 4K footage.

Approximate file sizes: JPEG photo: 2 to 8 MB · RAW photo: 20 to 50 MB · MP3 song: 3 to 10 MB · FLAC audio: 20 to 50 MB · SD video (1 hr): 1 to 2 GB · HD video (1 hr): 4 to 8 GB · 4K video (1 hr): 20 to 60 GB. Streaming services compress heavily: Netflix 4K uses about 7 GB/hr.

Modern computers (2026): Budget laptops: 8 GB · Mid-range laptops/desktops: 16 GB · High-end workstations: 32 to 64 GB · Servers: 128 GB to several TB. Smartphones typically have 8 to 16 GB RAM. A byte of RAM stores one character; 8 GB RAM can hold roughly 8 billion characters in memory simultaneously.

Standard SI prefixes go: KB → MB → GB → TB → PB (petabyte) → EB (exabyte) → ZB (zettabyte) → YB (yottabyte) → RB (ronnabyte) → QB (quettabyte). Ronna (1027) and quetta (1030) were added to the SI in November 2022, so the quettabyte is now the largest named unit. 1 YB = 1024 bytes, or one trillion TB.

Memory is sized in binary units, so 16 GB of RAM is 16 GiB = 17,179,869,184 bytes. That is 7.4% more than 16 billion bytes. Storage drives are the opposite: a 16 GB flash drive holds 16,000,000,000 bytes.

At full plan speed and with no overhead, 1 GB takes 80 seconds at 100 Mbps, 16 seconds at 500 Mbps and 8 seconds at 1 Gbps. The formula is: gigabytes × 8,000 ÷ Mbps = seconds. Real downloads are usually slower because of network overhead and the server's own speed.
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